Fix: Update all old-style imports inside packages to new paths

65 files in klausur-service packages + 3 in backend-lehrer packages
had stale imports referencing deleted shim modules.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

klausur-service/backend/ocr/pipeline/rows.py

@@ -17,7 +17,7 @@ import cv2
 import numpy as np
 from fastapi import APIRouter, HTTPException
 
-from cv_vocab_pipeline import (
+from ocr.cv_pipeline import (
     create_ocr_image,
     detect_column_geometry,
     detect_row_geometry,
@@ -120,7 +120,7 @@ async def detect_rows(session_id: str):
     # merges rows.  Word-grouping directly clusters words by Y proximity,
     # which is more robust for these cases.
     if is_sub_session and word_dicts:
-        from cv_layout import _build_rows_from_word_grouping
+        from ocr.layout.layout import _build_rows_from_word_grouping
         rows = _build_rows_from_word_grouping(
             word_dicts, left_x, right_x, top_y, bottom_y,
             right_x - left_x, bottom_y - top_y,